PHP Oauth building the signature key? - php

Question

I'm trying to build a valid signature key (I'm using the HMAC-SHA1 method), so far this is still invalid(i'm using an online test server at http://term.ie/oauth/example/client.php):
function _build_signature_hmac($base_url, $params, $consumer_key, $token_secret = '')
{
// Setup base-signature data
$data = 'POST&' . $base_url . '&';
// Sort the params array keys first
ksort($params);
// Attach params string
$data .= rawurlencode(http_build_query($params));
// Build the signature key
$key = rawurlencode($consumer_key) . '&' . rawurlencode($token_secret);
return base64_encode(hash_hmac('sha1', $data, $key));
}
Since this is a request for an unauthorized token, the $token_secret string is empty.
The returned signature looks like this:
POST&http://term.ie/oauth/example/request_token.php&oauth_consumer_key%3Dkey%26oauth_nonce%3D0uPOn3pPUbPlzWx2cO6citRPafIni5%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1298745681%26oauth_version%3D1.0
And the $key looks like this: secret&
The keys/secrets are all correct and I'm getting a response from the server saying 'invalid signature'. Am I building it the right way?

Answer 1

The method from the implementation I am using....
public function build_signature($request, $consumer, $token) {
$base_string = $request->get_signature_base_string();
$request->base_string = $base_string;
$key_parts = array(
$consumer->secret,
($token) ? $token->secret : ""
);
$key_parts = OAuthUtil::urlencode_rfc3986($key_parts);
$key = implode('&', $key_parts);
return base64_encode(hash_hmac('sha1', $base_string, $key, true));
}
public static function urlencode_rfc3986($input) {
if (is_array($input)) {
return array_map(array('OAuthUtil', 'urlencode_rfc3986'), $input);
} else if (is_scalar($input)) {
return str_replace(
'+',
' ',
str_replace('%7E', '~', rawurlencode($input))
);
} else {
return '';
}
If it helps at all...